On December 12, 2015, American Airlines flight 997, a Boeing 777, N784AN, encountered turbulence enroute to Ministro Pistarini International Airport, Buenos Aires, Argentina (EZE) during a regularly scheduled passenger flight from Dallas-Fort Worth International Airport (DFW), Dallas, Texas. The aircraft was approximately 250 NM from EZE and deviating north of the filed routing to avoid a strong convective area near thunderstorms. The flight crew had advised the flight attendants (FA) that the flight could encounter turbulence in approximately 15 minutes and they should be seated. The fasten seatbelt sign was on. While two FA's were securing the galley, the flight encountered the region of strong/severe turbulence earlier than expected. One FA was thrown to the floor and fell resulting in a broken arm. There were no passenger injuries and no damage to the airplane. The JIAIAC of Argentina delegated the investigation to the NTSB, who accepted the delegation.